In a universal mobile telecommunications system (UMTS), a radio resource control (RRC) connection state of user equipment (UE) includes a cell_dedicated channel (CELL_DCH) state, a cell_forward access channel (CELL_FACH) state, a cell_paging channel (CELL_PCH) state, and a UTRAN registration area paging channel (URA_PCH) state. CELL_DCH refers to that the UE is in an active state, the UE is using a dedicated channel of the UE to perform communication, both an uplink and a downlink have dedicated channels, and a network accurately knows a cell in which the user equipment is located. CELL_FACH refers to that the UE is in an active state, but both an uplink and a downlink have only a small amount of data that needs to be transmitted, and a network accurately knows a cell in which the UE is located. CELL_PCH refers to that neither an uplink nor a downlink of the UE has data to transfer, a paging indicator channel (PICH) needs to be listened on, so as to listen to paging, and the UE enters discontinuous reception in this case; therefore, power may be effectively saved, a network accurately knows a cell in which the UE is located, and after the cell in which the UE is located is changed, the network needs to update cell information of the UE. URA_PCH refers to that neither an uplink nor a downlink of the UE has data to transfer, a PICH needs to be listened on, the UE enters discontinuous reception, a network knows only a UTRAN registration area (URA) in which the UE is located, that is, the network updates location information of the UE only after a URA in which the UE is located is changed, thereby reducing resources and reducing signaling.
In a different RRC connection state, UE has a different data transmission capability and occupies a different communication resource. As a data transmission requirement changes, an RRC connection state of the UE needs to be switched among CELL_DCH, CELL_FACH, CELL_PCH, and URA_PCH, thereby achieving an objective of both meeting the data transmission requirement of the UE and reducing communication resources. For example, when the UE needs to send a large amount of data, a network instructs, by using downlink RRC signaling, the UE to enter CELL_DCH. When the UE needs to transmit only a small amount of data, the network may instruct, by using downlink RRC signaling, the UE to enter CELL_FACH. If the UE does not need to send data, the network may instruct, by using downlink RRC signaling, the UE to enter CELL_PCH.
In a different RRC connection state, a feature that can be enabled by UE is also different. Therefore, if a state of the UE transitions, a network further needs to configure a feature. The feature that can be enabled by the UE refers to a technical capability that is enabled by the UE and that can be supported by the UE. The technical capability is, for example, a high speed downlink packet access (HSDPA) capability, a dual-carrier high speed downlink packet access (DC-HSDPA) capability, a high speed uplink packet access (HSUPA) capability, a discontinuous transmission/discontinuous reception (DTX/DRX) capability, a four-carrier high speed downlink packet access (4C-HSDPAs) capability, or a dual-carrier high speed uplink packet access (DC-HSUPA) capability. In the prior art, if a feature to be activated needs to be activated, a network needs to add, to signaling sent to the UE, a configuration information element corresponding to the feature to be enabled. The configuration information element includes a configuration parameter needed to configure the feature to be enabled. For example, when the RRC connection state of the UE is transitioned to CELL_DCH, to improve a data transmission rate of the UE, the network may turn on multiple carriers. The multiple carriers refer to a feature of configuring multiple adjacent or nonadjacent carriers for the UE to improve the data transmission rate of the UE. When the UE needs to turn on multiple carriers, the network adds, to signaling sent to the UE, a configuration information element that corresponds to turning on of multiple carriers. When receiving the configuration information element, the UE performs configuration according to the configuration information element, to turn on multiple carriers.
The inventor finds that, when an existing feature configuration method is used, even if content of a configuration information element is not changed, each time UE needs to activate a feature to be activated, a network needs to send the configuration information element to the UE. Using an example of enabling a multiple-carrier feature having a same configuration parameter, each time a state of the UE is transitioned to CELL_DCH, a radio network controller needs to send a same configuration information element to the UE. It may be seen accordingly that when the existing feature configuration method is used, a same configuration information element is repetitively sent, which causes a waste of signaling resources, and reduces a success rate of signaling transmission of an air interface.